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LM5023: Over Voltage Protection latch during short

Joe Brant
Prodigy 30 points
Part Number: LM5023

Tool/software:

Hello,

I am currently working on a high voltage flyback design. I have the circuit working well, but during testing we have encountered an issue that isnt ideal.  When we execute a short on the output (UL Testing), we are seeing an overvoltage event on the QR pin.  The DUT goes into protection, but the LM5023 wont unlatch to allow the DUT to power up.  Is there anything that can be done to eliminate the OVP latch protection.  

  • 0
    TI__Mastermind 23745 points

    Hi Joe,

    Thank you for reaching out.

    Unfortunately I do not think latch functionality can be eliminated. 

    f this condition is causing a OVP fault to trigger, VCC needs to discharge below VRST (5V typ) before it can restart.  If the overload condition is exceeded, VCC needs to discharge below VCCOFF (7.5V typ) before it can restart.  

    If the OVP latch fault response is in fact causing the shutdown during this input cycle, you may need to discharge VCC faster so it can reduce below VRST (5V typ) to restart.  This could either be done by reducing the VCC capacitance or adding a circuit that pulls VCC down faster. I do not think we have an auto restart function without latch functionality for this IC.

    Regards,

    harish